This application claims the priority of German patent document 101 26 664.2, filed Jun. 1, 2001, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a fuel cell system having at least one fuel cell unit and means for detecting fuel leaks, and to a method for operating such a fuel cell system.
When fuel cell systems are operated, it is necessary to avoid accumulations of ignitable hydrogen in the system to the greatest extent possible. For example, German patent document DE 100 01 717, which is not prior art, discloses a fuel cell system in which Coanda flow boosters can be used at various locations in the fuel cell system in order to avoid dangerous build-ups of hydrogen or of fuel gases or fuel vapors.
International patent document WO 99/57335 Al, on the other hand, discloses an arrangement comprising fuel cells in which the use of explosion-protected components can be avoided. To protect electrical components from hydrogen leaks, an elevated pressure is provided at the corresponding area of the system, so that seepage of hydrogen is prevented.
One object of the invention is to provide a fuel cell system which is suitable specifically for mobile fuel cell installations.
This and other objects and advantages are achieved by the fuel cell system and method according to the invention, which has a housing in which components that operate at an elevated temperature are arranged. The housing may be thermally insulated, and its interior is evacuated via a suction line in which a hydrogen sensor may be arranged. The advantage of this arrangement is that the atmosphere in the interior of the housing reaches the hydrogen sensor in substantially undiluted form, so that even slight hydrogen leaks in the housing can be reliably detected before a critical concentration occurs.
The operational reliability of the fuel cell system is increased, and the build-up of undesirable quantities of hydrogen and/or build-ups of fuel gases or fuel vapors in the system can be effectively avoided.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.